All of these drugs are antiplatelet agents EXCEPT:

Correct Answer: B

Rationale: The correct answer is B: Urokinase. Urokinase is a thrombolytic agent that works by breaking down blood clots, not preventing platelet aggregation like the other options. Aspirin inhibits COX enzyme, Ticlopidine and Clopidogrel are both ADP receptor antagonists which prevent platelet activation. Therefore, urokinase does not belong to the class of antiplatelet agents.

Correct Answer: C

Rationale: Rationale: 1. Losartan is a non-peptide angiotensin II receptor antagonist. 2. Clonidine is a centrally acting alpha-2 adrenergic agonist. 3. Captopril is an ACE inhibitor. 4. Diazoxide is a potassium channel activator, used for hyperinsulinism. Therefore, the correct answer is C, as it specifically targets angiotensin II receptors, unlike the other choices.

Correct Answer: D

Rationale: The correct answer is D because many hormones actually exert their effects by interacting with specific receptors on the cell membrane rather than acting directly on subcellular membranes. This interaction triggers a series of intracellular events that lead to a cellular response. Option A is true as hormones indeed interact with specific receptors on cell walls. Option B is true as cyclic AMP is a common second messenger system utilized by hormones. Option C is true as many hormones stimulate adenylcyclase enzyme as part of their signaling pathway.

Correct Answer: A

Rationale: The correct answer is A, Repaglinide (Prandin), as it is not a biguanide but a meglitinide used for managing type 2 diabetes by stimulating insulin release. Metformin is a biguanide commonly used as a first-line treatment for type 2 diabetes due to its efficacy and safety profile. Phenformin is a biguanide that was withdrawn from the market due to its association with lactic acidosis. Glipizide is a sulfonylurea, not a biguanide, and works by stimulating insulin release from the pancreas. Therefore, A is the correct answer as it is not an oral hypoglycemic biguanide.

Correct Answer: B

Rationale: The correct answer is B: FALSE. COX-1 is constitutively expressed and involved in homeostatic functions, while COX-2 is inducible during inflammation to facilitate the inflammatory response. COX-1 is responsible for maintaining normal physiological functions, such as protecting the stomach lining and regulating blood flow, while COX-2 is primarily involved in producing prostaglandins during inflammation. Therefore, COX-1 is not induced during inflammation, and COX-2 is not homeostatic. Choice A is incorrect because COX-1, not COX-2, is homeostatic. Choice C is incorrect because there is a clear distinction between the functions of COX-1 and COX-2. Choice D is incorrect because not all options are correct; only option B is accurate based on the roles of COX-1 and COX-2 in the body.